Percentage of temporary faults vs. permanent faults

[Sideswiper]

Anyone have a statistic of how many distribution faults are temporary vs. permanent?

 

[waross]

Look at stats for reclosers. The majority of faults are cleared by the first or second operation of the recloser. These are usually birds, animals or falling tree branches.
The next greatest number of faults are distribution transformer failures. These faults are cleared by the later, longer reclosings of the reclosers.
Look for recloser brochures on manufacturers web sites. They will usually quote statistics.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[magoo2]

The answer is going to vary by utility. Some have a higher than normal amount of underground compared to overhead, so their percentage of temporary faults would be fairly low.

The usual quote for distribution overcurrent protection is that approximately 75 to 80% of the faults are temporary.

 

[Sideswiper]

I got the information I needed from "Electric Power Distribution Handbook" by Tom A. Short. There's a preview of some pages on google books.

http://books.google.com/books?id=CT...t=html&sig=ACfU3U346ieI4uIq6TgIiZ6-QDQTms0j-w

My boss told me to go ahead and order a copy of the book, which is nice.